When an email message arrives with an attachment (file type doesn't matter at this point), I would like to save that attachment to disk, and mark the message as 'read' in the mailbox. I will only be using a single mailbox for this project.

In the past I have used licensed software to do this so I know it is possible, but I would now like to create my own solution for this. I have good working knowledge of .Net (vb.Net and C#.Net), but not where Office add-ins are concerned, so I need a bit of direction here.

Can anyone tell me how to accomplish the above? With the licensed software it was necessary to keep an account logged in to Outlook at all times. I assume that if I stay with an Outlook Add-In this will also be the case. If it can be done with a service running on the exchange server that would be even better.